/*
 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.eclipse.imagen.media.opimage;

import java.awt.Rectangle;
import java.awt.image.DataBuffer;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;
import java.util.Map;
import org.eclipse.imagen.BorderExtender;
import org.eclipse.imagen.ImageLayout;
import org.eclipse.imagen.Interpolation;
import org.eclipse.imagen.RasterAccessor;
import org.eclipse.imagen.RasterFormatTag;
import org.eclipse.imagen.ScaleOpImage;
import org.eclipse.imagen.media.util.Rational;
// import org.eclipse.imagen.media.test.OpImageTester;

/** An <code>OpImage</code> that performs bilinear interpolation scaling. */
final class ScaleBilinearOpImage extends ScaleOpImage {

    /** The number of SubsampleBits */
    private int subsampleBits;

    /** Subsampling related variables */
    int one, shift2, round2;

    Rational half = new Rational(1, 2);
    long invScaleYInt, invScaleYFrac;
    long invScaleXInt, invScaleXFrac;

    /**
     * Constructs a ScaleBilinearOpImage from a RenderedImage source,
     *
     * @param source a RenderedImage.
     * @param extender a BorderExtender, or null.
     * @param layout an ImageLayout optionally containing the tile grid layout, SampleModel, and ColorModel, or null.
     * @param xScale scale factor along x axis.
     * @param yScale scale factor along y axis.
     * @param xTrans translation factor along x axis.
     * @param yTrans translation factor along y axis.
     * @param interp a Interpolation object to use for resampling.
     */
    public ScaleBilinearOpImage(
            RenderedImage source,
            BorderExtender extender,
            Map config,
            ImageLayout layout,
            float xScale,
            float yScale,
            float xTrans,
            float yTrans,
            Interpolation interp) {
        super(source, layout, config, true, extender, interp, xScale, yScale, xTrans, yTrans);

        subsampleBits = interp.getSubsampleBitsH();

        // Number of subsampling positions
        one = 1 << subsampleBits;

        // Subsampling related variables
        shift2 = 2 * subsampleBits;
        round2 = 1 << (shift2 - 1);

        if (invScaleYRational.num > invScaleYRational.denom) {
            invScaleYInt = invScaleYRational.num / invScaleYRational.denom;
            invScaleYFrac = invScaleYRational.num % invScaleYRational.denom;
        } else {
            invScaleYInt = 0;
            invScaleYFrac = invScaleYRational.num;
        }

        if (invScaleXRational.num > invScaleXRational.denom) {
            invScaleXInt = invScaleXRational.num / invScaleXRational.denom;
            invScaleXFrac = invScaleXRational.num % invScaleXRational.denom;
        } else {
            invScaleXInt = 0;
            invScaleXFrac = invScaleXRational.num;
        }
    }

    /**
     * Performs scale operation on a specified rectangle. The sources are cobbled.
     *
     * @param sources an array of source Rasters, guaranteed to provide all necessary source data for computing the
     *     output.
     * @param dest a WritableRaster tile containing the area to be computed.
     * @param destRect the rectangle within dest to be processed.
     */
    protected void computeRect(Raster[] sources, WritableRaster dest, Rectangle destRect) {
        // Retrieve format tags.
        RasterFormatTag[] formatTags = getFormatTags();

        Raster source = sources[0];
        // Get the source rectangle
        Rectangle srcRect = source.getBounds();

        RasterAccessor srcAccessor =
                new RasterAccessor(source, srcRect, formatTags[0], getSource(0).getColorModel());

        RasterAccessor dstAccessor = new RasterAccessor(dest, destRect, formatTags[1], getColorModel());

        int dwidth = destRect.width;
        int dheight = destRect.height;
        int srcPixelStride = srcAccessor.getPixelStride();
        int srcScanlineStride = srcAccessor.getScanlineStride();

        int[] ypos = new int[dheight];
        int[] xpos = new int[dwidth];

        int xfracvalues[] = null, yfracvalues[] = null;
        float xfracvaluesFloat[] = null, yfracvaluesFloat[] = null;

        switch (dstAccessor.getDataType()) {
            case DataBuffer.TYPE_BYTE:
            case DataBuffer.TYPE_SHORT:
            case DataBuffer.TYPE_USHORT:
            case DataBuffer.TYPE_INT:
                yfracvalues = new int[dheight];
                xfracvalues = new int[dwidth];
                preComputePositionsInt(
                        destRect,
                        srcRect.x,
                        srcRect.y,
                        srcPixelStride,
                        srcScanlineStride,
                        xpos,
                        ypos,
                        xfracvalues,
                        yfracvalues);
                break;

            case DataBuffer.TYPE_FLOAT:
            case DataBuffer.TYPE_DOUBLE:
                yfracvaluesFloat = new float[dheight];
                xfracvaluesFloat = new float[dwidth];
                preComputePositionsFloat(
                        destRect,
                        srcRect.x,
                        srcRect.y,
                        srcPixelStride,
                        srcScanlineStride,
                        xpos,
                        ypos,
                        xfracvaluesFloat,
                        yfracvaluesFloat);
                break;

            default:
                throw new RuntimeException(JaiI18N.getString("OrderedDitherOpImage0"));
        }

        switch (dstAccessor.getDataType()) {
            case DataBuffer.TYPE_BYTE:
                byteLoop(srcAccessor, destRect, dstAccessor, xpos, ypos, xfracvalues, yfracvalues);
                break;

            case DataBuffer.TYPE_SHORT:
                shortLoop(srcAccessor, destRect, dstAccessor, xpos, ypos, xfracvalues, yfracvalues);
                break;

            case DataBuffer.TYPE_USHORT:
                ushortLoop(srcAccessor, destRect, dstAccessor, xpos, ypos, xfracvalues, yfracvalues);
                break;

            case DataBuffer.TYPE_INT:
                intLoop(srcAccessor, destRect, dstAccessor, xpos, ypos, xfracvalues, yfracvalues);
                break;

            case DataBuffer.TYPE_FLOAT:
                floatLoop(srcAccessor, destRect, dstAccessor, xpos, ypos, xfracvaluesFloat, yfracvaluesFloat);
                break;

            case DataBuffer.TYPE_DOUBLE:
                doubleLoop(srcAccessor, destRect, dstAccessor, xpos, ypos, xfracvaluesFloat, yfracvaluesFloat);
                break;
        }

        // If the RasterAccessor object set up a temporary buffer for the
        // op to write to, tell the RasterAccessor to write that data
        // to the raster no that we're done with it.
        if (dstAccessor.isDataCopy()) {
            dstAccessor.clampDataArrays();
            dstAccessor.copyDataToRaster();
        }
    }

    private void preComputePositionsInt(
            Rectangle destRect,
            int srcRectX,
            int srcRectY,
            int srcPixelStride,
            int srcScanlineStride,
            int xpos[],
            int ypos[],
            int xfracvalues[],
            int yfracvalues[]) {

        int dwidth = destRect.width;
        int dheight = destRect.height;

        // Loop variables based on the destination rectangle to be calculated.
        int dx = destRect.x;
        int dy = destRect.y;

        long syNum = dy, syDenom = 1;

        // Subtract the X translation factor sy -= transY
        syNum = syNum * transYRationalDenom - transYRationalNum * syDenom;
        syDenom *= transYRationalDenom;

        // Add 0.5
        syNum = 2 * syNum + syDenom;
        syDenom *= 2;

        // Multply by invScaleX
        syNum *= invScaleYRationalNum;
        syDenom *= invScaleYRationalDenom;

        // Subtract 0.5
        syNum = 2 * syNum - syDenom;
        syDenom *= 2;

        // Separate the x source coordinate into integer and fractional part
        int srcYInt = Rational.floor(syNum, syDenom);
        long srcYFrac = syNum % syDenom;
        if (srcYInt < 0) {
            srcYFrac = syDenom + srcYFrac;
        }

        // Normalize - Get a common denominator for the fracs of
        // src and invScaleY
        long commonYDenom = syDenom * invScaleYRationalDenom;
        srcYFrac *= invScaleYRationalDenom;
        long newInvScaleYFrac = invScaleYFrac * syDenom;

        // Precalculate the x positions and store them in an array.
        long sxNum = dx, sxDenom = 1;

        // Subtract the X translation factor sx -= transX
        sxNum = sxNum * transXRationalDenom - transXRationalNum * sxDenom;
        sxDenom *= transXRationalDenom;

        // Add 0.5
        sxNum = 2 * sxNum + sxDenom;
        sxDenom *= 2;

        // Multply by invScaleX
        sxNum *= invScaleXRationalNum;
        sxDenom *= invScaleXRationalDenom;

        // Subtract 0.5
        sxNum = 2 * sxNum - sxDenom;
        sxDenom *= 2;

        // Separate the x source coordinate into integer and fractional part
        int srcXInt = Rational.floor(sxNum, sxDenom);
        long srcXFrac = sxNum % sxDenom;
        if (srcXInt < 0) {
            srcXFrac = sxDenom + srcXFrac;
        }

        // Normalize - Get a common denominator for the fracs of
        // src and invScaleX
        long commonXDenom = sxDenom * invScaleXRationalDenom;
        srcXFrac *= invScaleXRationalDenom;
        long newInvScaleXFrac = invScaleXFrac * sxDenom;

        for (int i = 0; i < dwidth; i++) {
            xpos[i] = (srcXInt - srcRectX) * srcPixelStride;
            xfracvalues[i] = (int) (((float) srcXFrac / (float) commonXDenom) * one);

            // Move onto the next source pixel.

            // Add the integral part of invScaleX to the integral part
            // of srcX
            srcXInt += invScaleXInt;

            // Add the fractional part of invScaleX to the fractional part
            // of srcX
            srcXFrac += newInvScaleXFrac;

            // If the fractional part is now greater than equal to the
            // denominator, divide so as to reduce the numerator to be less
            // than the denominator and add the overflow to the integral part.
            if (srcXFrac >= commonXDenom) {
                srcXInt += 1;
                srcXFrac -= commonXDenom;
            }
        }

        for (int i = 0; i < dheight; i++) {

            // Calculate the source position in the source data array.
            ypos[i] = (srcYInt - srcRectY) * srcScanlineStride;

            // Calculate the yfrac value
            yfracvalues[i] = (int) (((float) srcYFrac / (float) commonYDenom) * one);

            // Move onto the next source pixel.

            // Add the integral part of invScaleY to the integral part
            // of srcY
            srcYInt += invScaleYInt;

            // Add the fractional part of invScaleY to the fractional part
            // of srcY
            srcYFrac += newInvScaleYFrac;

            // If the fractional part is now greater than equal to the
            // denominator, divide so as to reduce the numerator to be less
            // than the denominator and add the overflow to the integral part.
            if (srcYFrac >= commonYDenom) {
                srcYInt += 1;
                srcYFrac -= commonYDenom;
            }
        }
    }

    private void preComputePositionsFloat(
            Rectangle destRect,
            int srcRectX,
            int srcRectY,
            int srcPixelStride,
            int srcScanlineStride,
            int xpos[],
            int ypos[],
            float xfracvaluesFloat[],
            float yfracvaluesFloat[]) {

        int dwidth = destRect.width;
        int dheight = destRect.height;

        // Loop variables based on the destination rectangle to be calculated.
        int dx = destRect.x;
        int dy = destRect.y;

        long syNum = dy, syDenom = 1;

        // Subtract the X translation factor sy -= transY
        syNum = syNum * transYRationalDenom - transYRationalNum * syDenom;
        syDenom *= transYRationalDenom;

        // Add 0.5
        syNum = 2 * syNum + syDenom;
        syDenom *= 2;

        // Multply by invScaleX
        syNum *= invScaleYRationalNum;
        syDenom *= invScaleYRationalDenom;

        // Subtract 0.5
        syNum = 2 * syNum - syDenom;
        syDenom *= 2;

        // Separate the x source coordinate into integer and fractional part
        int srcYInt = Rational.floor(syNum, syDenom);
        long srcYFrac = syNum % syDenom;
        if (srcYInt < 0) {
            srcYFrac = syDenom + srcYFrac;
        }

        // Normalize - Get a common denominator for the fracs of
        // src and invScaleY
        long commonYDenom = syDenom * invScaleYRationalDenom;
        srcYFrac *= invScaleYRationalDenom;
        long newInvScaleYFrac = invScaleYFrac * syDenom;

        // Precalculate the x positions and store them in an array.
        long sxNum = dx, sxDenom = 1;

        // Subtract the X translation factor sx -= transX
        sxNum = sxNum * transXRationalDenom - transXRationalNum * sxDenom;
        sxDenom *= transXRationalDenom;

        // Add 0.5
        sxNum = 2 * sxNum + sxDenom;
        sxDenom *= 2;

        // Multply by invScaleX
        sxNum *= invScaleXRationalNum;
        sxDenom *= invScaleXRationalDenom;

        // Subtract 0.5
        sxNum = 2 * sxNum - sxDenom;
        sxDenom *= 2;

        // Separate the x source coordinate into integer and fractional part
        int srcXInt = Rational.floor(sxNum, sxDenom);
        long srcXFrac = sxNum % sxDenom;
        if (srcXInt < 0) {
            srcXFrac = sxDenom + srcXFrac;
        }

        // Normalize - Get a common denominator for the fracs of
        // src and invScaleX
        long commonXDenom = sxDenom * invScaleXRationalDenom;
        srcXFrac *= invScaleXRationalDenom;
        long newInvScaleXFrac = invScaleXFrac * sxDenom;

        for (int i = 0; i < dwidth; i++) {

            xpos[i] = (srcXInt - srcRectX) * srcPixelStride;
            xfracvaluesFloat[i] = (float) srcXFrac / (float) commonXDenom;

            // Move onto the next source pixel.

            // Add the integral part of invScaleX to the integral part
            // of srcX
            srcXInt += invScaleXInt;

            // Add the fractional part of invScaleX to the fractional part
            // of srcX
            srcXFrac += newInvScaleXFrac;

            // If the fractional part is now greater than equal to the
            // denominator, divide so as to reduce the numerator to be less
            // than the denominator and add the overflow to the integral part.
            if (srcXFrac >= commonXDenom) {
                srcXInt += 1;
                srcXFrac -= commonXDenom;
            }
        }

        for (int i = 0; i < dheight; i++) {

            // Calculate the source position in the source data array.
            ypos[i] = (srcYInt - srcRectY) * srcScanlineStride;

            // Calculate the yfrac value
            yfracvaluesFloat[i] = (float) srcYFrac / (float) commonYDenom;

            // Move onto the next source pixel.

            // Add the integral part of invScaleY to the integral part
            // of srcY
            srcYInt += invScaleYInt;

            // Add the fractional part of invScaleY to the fractional part
            // of srcY
            srcYFrac += newInvScaleYFrac;

            // If the fractional part is now greater than equal to the
            // denominator, divide so as to reduce the numerator to be less
            // than the denominator and add the overflow to the integral part.
            if (srcYFrac >= commonYDenom) {
                srcYInt += 1;
                srcYFrac -= commonYDenom;
            }
        }
    }

    private void byteLoop(
            RasterAccessor src,
            Rectangle dstRect,
            RasterAccessor dst,
            int xpos[],
            int ypos[],
            int xfracvalues[],
            int yfracvalues[]) {

        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();
        int srcLastXDataPos = (src.getWidth() - 1) * srcPixelStride;

        int dwidth = dstRect.width;
        int dheight = dstRect.height;
        int dnumBands = dst.getNumBands();
        byte dstDataArrays[][] = dst.getByteDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        byte srcDataArrays[][] = src.getByteDataArrays();
        int bandOffsets[] = src.getBandOffsets();

        int dstOffset = 0;

        /* Four surrounding pixels are needed for Bilinear interpolation.
         * If the dest pixel to be calculated is at (dx, dy) then the
         * actual source pixel (sx, sy) required is (dx/scaleX, dy/scaleY).
         * The four pixels that surround it are at the positions:
         * s00 = src(sxlow, sylow)
         * s01 = src(sxhigh, sylow)
         * s10 = src(sxlow, syhigh)
         * s11 = src(sxhigh, syhigh)
         * where sxlow = Math.floor(sx), sxhigh = Math.ceil(sx)
         * and   sylow = Math.floor(sy), syhigh = Math.ceil(sy)
         *
         * The value of the destination pixel can now be calculated as:
         * s0 = (s01 - s00)*xfrac + s00;
         * s1 = (s11 - s10)*xfrac + s10;
         * dst(x,y) = (s1 - s0)*yfrac + s0;
         */

        int posylow, posyhigh, posxlow, posxhigh;
        int s00, s01, s10, s11;

        // Precalculate the y positions and store them in an array.
        int xfrac, yfrac;
        int s, s0, s1;

        // Putting band loop outside
        for (int k = 0; k < dnumBands; k++) {
            byte dstData[] = dstDataArrays[k];
            byte srcData[] = srcDataArrays[k];
            int dstScanlineOffset = dstBandOffsets[k];
            int bandOffset = bandOffsets[k];
            for (int j = 0; j < dheight; j++) {

                int dstPixelOffset = dstScanlineOffset;
                yfrac = yfracvalues[j];
                posylow = ypos[j] + bandOffset;
                posyhigh = posylow + srcScanlineStride;

                for (int i = 0; i < dwidth; i++) {
                    xfrac = xfracvalues[i];
                    posxlow = xpos[i];
                    posxhigh = posxlow + srcPixelStride;

                    // Get the four surrounding pixel values
                    s00 = srcData[posxlow + posylow] & 0xff;
                    s01 = srcData[posxhigh + posylow] & 0xff;
                    s10 = srcData[posxlow + posyhigh] & 0xff;
                    s11 = srcData[posxhigh + posyhigh] & 0xff;

                    // Perform the bilinear interpolation
                    s0 = (s01 - s00) * xfrac + (s00 << subsampleBits);
                    s1 = (s11 - s10) * xfrac + (s10 << subsampleBits);
                    s = ((s1 - s0) * yfrac + (s0 << subsampleBits) + round2) >> shift2;

                    dstData[dstPixelOffset] = (byte) (s & 0xff);
                    dstPixelOffset += dstPixelStride;
                }
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void shortLoop(
            RasterAccessor src,
            Rectangle dstRect,
            RasterAccessor dst,
            int xpos[],
            int ypos[],
            int xfracvalues[],
            int yfracvalues[]) {

        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();
        int srcLastXDataPos = (src.getWidth() - 1) * srcPixelStride;

        int dwidth = dstRect.width;
        int dheight = dstRect.height;
        int dnumBands = dst.getNumBands();
        short dstDataArrays[][] = dst.getShortDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        short srcDataArrays[][] = src.getShortDataArrays();
        int bandOffsets[] = src.getBandOffsets();

        int dstOffset = 0;
        int posylow, posyhigh, posxlow, posxhigh;
        int s00, s01, s10, s11, s0, s1, s;
        int xfrac, yfrac;

        // Putting band loop outside
        for (int k = 0; k < dnumBands; k++) {
            short dstData[] = dstDataArrays[k];
            short srcData[] = srcDataArrays[k];
            int dstScanlineOffset = dstBandOffsets[k];
            int bandOffset = bandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int dstPixelOffset = dstScanlineOffset;
                yfrac = yfracvalues[j];
                posylow = ypos[j] + bandOffset;
                posyhigh = posylow + srcScanlineStride;

                for (int i = 0; i < dwidth; i++) {
                    xfrac = xfracvalues[i];
                    posxlow = xpos[i];
                    posxhigh = posxlow + srcPixelStride;

                    // Get the four surrounding pixel values
                    s00 = srcData[posxlow + posylow];
                    s01 = srcData[posxhigh + posylow];
                    s10 = srcData[posxlow + posyhigh];
                    s11 = srcData[posxhigh + posyhigh];

                    // Perform the bilinear interpolation
                    s0 = (s01 - s00) * xfrac + (s00 << subsampleBits);
                    s1 = (s11 - s10) * xfrac + (s10 << subsampleBits);
                    s = ((s1 - s0) * yfrac + (s0 << subsampleBits) + round2) >> shift2;

                    dstData[dstPixelOffset] = (short) s;
                    dstPixelOffset += dstPixelStride;
                }
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void ushortLoop(
            RasterAccessor src,
            Rectangle dstRect,
            RasterAccessor dst,
            int xpos[],
            int ypos[],
            int xfracvalues[],
            int yfracvalues[]) {

        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();
        int srcLastXDataPos = (src.getWidth() - 1) * srcPixelStride;

        int dwidth = dstRect.width;
        int dheight = dstRect.height;
        int dnumBands = dst.getNumBands();
        short dstDataArrays[][] = dst.getShortDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        short srcDataArrays[][] = src.getShortDataArrays();
        int bandOffsets[] = src.getBandOffsets();

        int dstOffset = 0;
        int posylow, posyhigh, posxlow, posxhigh;
        int s00, s01, s10, s11, s0, s1, s;
        int xfrac, yfrac;

        // Putting band loop outside
        for (int k = 0; k < dnumBands; k++) {
            short dstData[] = dstDataArrays[k];
            short srcData[] = srcDataArrays[k];
            int dstScanlineOffset = dstBandOffsets[k];
            int bandOffset = bandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int dstPixelOffset = dstScanlineOffset;
                yfrac = yfracvalues[j];
                posylow = ypos[j] + bandOffset;
                posyhigh = posylow + srcScanlineStride;

                for (int i = 0; i < dwidth; i++) {
                    xfrac = xfracvalues[i];
                    posxlow = xpos[i];
                    posxhigh = posxlow + srcPixelStride;

                    // Get the four surrounding pixel values
                    s00 = srcData[posxlow + posylow] & 0xffff;
                    s01 = srcData[posxhigh + posylow] & 0xffff;
                    s10 = srcData[posxlow + posyhigh] & 0xffff;
                    s11 = srcData[posxhigh + posyhigh] & 0xffff;

                    // Perform the bilinear interpolation
                    s0 = (s01 - s00) * xfrac + (s00 << subsampleBits);
                    s1 = (s11 - s10) * xfrac + (s10 << subsampleBits);
                    s = ((s1 - s0) * yfrac + (s0 << subsampleBits) + round2) >> shift2;

                    dstData[dstPixelOffset] = (short) (s & 0xffff);
                    dstPixelOffset += dstPixelStride;
                }
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    // identical to byteLoops, except datatypes have changed.  clumsy,
    // but there's no other way in Java
    private void intLoop(
            RasterAccessor src,
            Rectangle dstRect,
            RasterAccessor dst,
            int xpos[],
            int ypos[],
            int xfracvalues[],
            int yfracvalues[]) {

        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();
        int srcLastXDataPos = (src.getWidth() - 1) * srcPixelStride;

        int dwidth = dstRect.width;
        int dheight = dstRect.height;
        int dnumBands = dst.getNumBands();
        int dstDataArrays[][] = dst.getIntDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        int srcDataArrays[][] = src.getIntDataArrays();
        int bandOffsets[] = src.getBandOffsets();

        int dstOffset = 0;
        int posylow, posyhigh, posxlow, posxhigh;
        int s00, s10, s01, s11;
        long s0, s1;
        int xfrac, yfrac;
        int shift = 29 - subsampleBits;

        // Putting band loop outside
        for (int k = 0; k < dnumBands; k++) {
            int dstData[] = dstDataArrays[k];
            int srcData[] = srcDataArrays[k];
            int dstScanlineOffset = dstBandOffsets[k];
            int bandOffset = bandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int dstPixelOffset = dstScanlineOffset;
                yfrac = yfracvalues[j];
                posylow = ypos[j] + bandOffset;
                posyhigh = posylow + srcScanlineStride;

                for (int i = 0; i < dwidth; i++) {
                    xfrac = xfracvalues[i];
                    posxlow = xpos[i];
                    posxhigh = posxlow + srcPixelStride;

                    // Get the four surrounding pixel values
                    s00 = srcData[posxlow + posylow];
                    s01 = srcData[posxhigh + posylow];
                    s10 = srcData[posxlow + posyhigh];
                    s11 = srcData[posxhigh + posyhigh];

                    // Perform the bilinear interpolation
                    if ((s00 | s10) >>> shift == 0) {
                        if ((s01 | s11) >>> shift == 0) {
                            s0 = (s01 - s00) * xfrac + (s00 << subsampleBits);
                            s1 = (s11 - s10) * xfrac + (s10 << subsampleBits);
                        } else {
                            s0 = ((long) s01 - s00) * xfrac + (s00 << subsampleBits);
                            s1 = ((long) s11 - s10) * xfrac + (s10 << subsampleBits);
                        }
                    } else {
                        s0 = ((long) s01 - s00) * xfrac + ((long) s00 << subsampleBits);
                        s1 = ((long) s11 - s10) * xfrac + ((long) s10 << subsampleBits);
                    }

                    dstData[dstPixelOffset] = (int) (((s1 - s0) * yfrac + (s0 << subsampleBits) + round2) >> shift2);

                    dstPixelOffset += dstPixelStride;
                }
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    // Interpolation for floating point samples done as specified by the
    // following formula:
    //        float s0 = (s01 - s00)*xfrac + s00;
    //        float s1 = (s11 - s10)*xfrac + s10;
    //        return (s1 - s0)*yfrac + s0;
    // Note that xfrac, yfrac are in the range [0.0F, 1.0F)

    private void floatLoop(
            RasterAccessor src,
            Rectangle dstRect,
            RasterAccessor dst,
            int xpos[],
            int ypos[],
            float xfracvaluesFloat[],
            float yfracvaluesFloat[]) {

        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();
        int srcLastXDataPos = (src.getWidth() - 1) * srcPixelStride;

        int dwidth = dstRect.width;
        int dheight = dstRect.height;
        int dnumBands = dst.getNumBands();
        float dstDataArrays[][] = dst.getFloatDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        float srcDataArrays[][] = src.getFloatDataArrays();
        int bandOffsets[] = src.getBandOffsets();

        float s00, s01, s10, s11;
        float s0, s1;
        float xfrac, yfrac;
        int dstOffset = 0;
        int posylow, posyhigh, posxlow, posxhigh;

        // Putting band loop outside
        for (int k = 0; k < dnumBands; k++) {
            float dstData[] = dstDataArrays[k];
            float srcData[] = srcDataArrays[k];
            int dstScanlineOffset = dstBandOffsets[k];
            int bandOffset = bandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int dstPixelOffset = dstScanlineOffset;
                yfrac = yfracvaluesFloat[j];
                posylow = ypos[j] + bandOffset;
                posyhigh = posylow + srcScanlineStride;

                for (int i = 0; i < dwidth; i++) {
                    xfrac = xfracvaluesFloat[i];
                    posxlow = xpos[i];
                    posxhigh = posxlow + srcPixelStride;

                    // Get the four surrounding pixel values
                    s00 = srcData[posxlow + posylow];
                    s01 = srcData[posxhigh + posylow];
                    s10 = srcData[posxlow + posyhigh];
                    s11 = srcData[posxhigh + posyhigh];

                    // Perform the bilinear interpolation
                    s0 = (s01 - s00) * xfrac + s00;
                    s1 = (s11 - s10) * xfrac + s10;

                    dstData[dstPixelOffset] = (s1 - s0) * yfrac + s0;

                    dstPixelOffset += dstPixelStride;
                }
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void doubleLoop(
            RasterAccessor src,
            Rectangle dstRect,
            RasterAccessor dst,
            int xpos[],
            int ypos[],
            float xfracvaluesFloat[],
            float yfracvaluesFloat[]) {

        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();
        int srcLastXDataPos = (src.getWidth() - 1) * srcPixelStride;

        int dwidth = dstRect.width;
        int dheight = dstRect.height;
        int dnumBands = dst.getNumBands();
        double dstDataArrays[][] = dst.getDoubleDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        double srcDataArrays[][] = src.getDoubleDataArrays();
        int bandOffsets[] = src.getBandOffsets();

        double s00, s01, s10, s11;
        double s0, s1;
        double xfrac, yfrac;
        int dstOffset = 0;
        int posylow, posyhigh, posxlow, posxhigh;

        // Putting band loop outside
        for (int k = 0; k < dnumBands; k++) {
            double dstData[] = dstDataArrays[k];
            double srcData[] = srcDataArrays[k];
            int dstScanlineOffset = dstBandOffsets[k];
            int bandOffset = bandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int dstPixelOffset = dstScanlineOffset;
                yfrac = yfracvaluesFloat[j];
                posylow = ypos[j] + bandOffset;
                posyhigh = posylow + srcScanlineStride;

                for (int i = 0; i < dwidth; i++) {
                    xfrac = xfracvaluesFloat[i];
                    posxlow = xpos[i];
                    posxhigh = posxlow + srcPixelStride;

                    // Get the four surrounding pixel values
                    s00 = srcData[posxlow + posylow];
                    s01 = srcData[posxhigh + posylow];
                    s10 = srcData[posxlow + posyhigh];
                    s11 = srcData[posxhigh + posyhigh];

                    // Perform the bilinear interpolation
                    s0 = (s01 - s00) * xfrac + s00;
                    s1 = (s11 - s10) * xfrac + s10;

                    dstData[dstPixelOffset] = (s1 - s0) * yfrac + s0;

                    dstPixelOffset += dstPixelStride;
                }
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    //     public static OpImage createTestImage(OpImageTester oit) {
    //         Interpolation interp =
    //             Interpolation.getInstance(Interpolation.INTERP_BILINEAR);
    //         return new ScaleBilinearOpImage(oit.getSource(), null, null,
    //                                         new ImageLayout(oit.getSource()),
    //                                         2.5F, 2.5F, 0.0F, 0.0F,
    //                                         interp);
    //     }

    //     public static void main(String args[]) {
    //         String classname = "org.eclipse.imagen.media.opimage.ScaleBilinearOpImage";
    // 	OpImageTester.performDiagnostics(classname,args);
    // 	System.exit(1);

    //         System.out.println("ScaleOpImage Test");
    //         ImageLayout layout;
    //         OpImage src, dst;
    //         Rectangle rect = new Rectangle(0, 0, 5, 5);

    // 	InterpolationBilinear interp = new InterpolationBilinear();

    //         System.out.println("1. PixelInterleaved short 3-band");
    //         layout = OpImageTester.createImageLayout(
    //             0, 0, 200, 200, 0, 0, 64, 64, DataBuffer.TYPE_SHORT, 3, false);
    //         src = OpImageTester.createRandomOpImage(layout);
    //         dst = new ScaleBilinearOpImage(src, null, null, null,
    //                                        2.0F, 2.0F, 0.0F, 0.0F, interp);
    //         OpImageTester.testOpImage(dst, rect);
    //         OpImageTester.timeOpImage(dst, 10);

    //         System.out.println("2. PixelInterleaved ushort 3-band");
    //         layout = OpImageTester.createImageLayout(
    //             0, 0, 512, 512, 0, 0, 200, 200, DataBuffer.TYPE_USHORT, 3, false);
    //         src = OpImageTester.createRandomOpImage(layout);
    //         dst = new ScaleBilinearOpImage(src, null, null, null,
    //                                        2.0F, 2.0F, 0.0F, 0.0F, interp);
    //         OpImageTester.testOpImage(dst, rect);
    //         OpImageTester.timeOpImage(dst, 10);

    //         System.out.println("3. PixelInterleaved float 3-band");
    //         layout = OpImageTester.createImageLayout(0, 0, 512, 512, 0, 0, 200, 200,
    // 						 DataBuffer.TYPE_FLOAT, 3,
    // 						 false);
    //         src = OpImageTester.createRandomOpImage(layout);
    //         dst = new ScaleBilinearOpImage(src, null, null, null,
    //                                        2.0F, 2.0F, 0.0F, 0.0F, interp);
    //         OpImageTester.testOpImage(dst, rect);
    //         OpImageTester.timeOpImage(dst, 10);

    //         System.out.println("4. PixelInterleaved double 3-band");
    //         layout = OpImageTester.createImageLayout(0, 0, 512, 512,
    //                                                  0, 0, 200, 200,
    // 						 DataBuffer.TYPE_DOUBLE, 3,
    // 						 false);
    //         src = OpImageTester.createRandomOpImage(layout);
    //         dst = new ScaleBilinearOpImage(src, null, null, null,
    //                                        2.0F, 2.0F, 0.0F, 0.0F, interp);
    //         OpImageTester.testOpImage(dst, rect);
    //         OpImageTester.timeOpImage(dst, 10);
    //     }
}
